trainer smacking on the haunches outside the gates

Question

smack haunches   hello sir, one trainer at our racetrack smacks the horse on its haunches once it is loaded in the gates and as soon as the start is given gate training session. may i know why does he do like that? i believe that the horse get spooked. am i right? you can have a clear view of the image i have attached. in this image, the trainer is standing with a whip in his hand outside the training gates. horse is loaded inside the gates with rider atop.

Answer
This is true as this may be done to cause a horse to jump out in fear, but I do not believe in this method unless absolutely necessary for a certain kind of horse. A rider should be able to coax a horse out faster every attempt until he learns that he is allowed to burst out of the gate. Hitting a horse, while in the gate, can do more harm than good. A horse may become very anxious and eventually become a bad actor in the gate if he fears pressure while he is in it. He should feel very relaxed and safe in the gate and break out because he WANTS to run, not because he is forced to or afraid not to.